Dutch and Belgian investigators launched joint raids on Thursday over Europe’s insecticide-tainted egg scare as Britain said it had imported far more contaminated eggs than originally revealed.

The spiralling scandal also spread to an eighth country, Luxembourg, which announced that it too had found eggs containing the insecticide fipronil, which can be harmful to human health.

Millions of eggs have been destroyed or taken off the shelves across Europe with growing questions about the extent to which consumers have been kept in the dark over the scale of the problem.

Fipronil is commonly used to get rid of fleas, lice and ticks from animals but is banned by the EU from use in the food industry. It can harm people’s kidneys, liver and thyroid glands.

In the Netherlands and Belgium, the countries at the epicentre of the scare, authorities said they carried out coordinated searches at several premises linked to a fraud probe about how fipronil got into the food chain.

“There are several raids being held in The Netherlands, in conjunction with the Belgians,” Dutch public prosecution service spokeswoman Marieke van der Molen told AFP, but declined to give further details.

A spokeswoman for the prosecutor in Belgium’s northern port city of Antwerp said in a statement: “In connection with the fipronil case, several raids are currently being carried out.”

The joint action came despite Belgium one day earlier accusing the Netherlands of knowing about the problem of fipronil in eggs since November 2016, but failing to inform them until July.

The Belgian searches took place at eight sites in the Flanders region of Belgium, near the border with the Netherlands, Het Laatste Nieuws newspaper reported.

Britain boost egg numbers

Meanwhile British authorities said that around 700 000 eggs from Dutch farms implicated in the scandal had been distributed in Britain, just days after saying the number was only 21 000.

As a result, four major British supermarket chains have withdrawn some products containing eggs, including sandwiches and salads, the Food Standards Agency said.

“It is likely that the number of eggs that have come to the UK is closer to 700 000 than the 21 000 we previously believed had been imported,” the agency said, adding that this represents just 0.007% of the eggs consumed in Britain every year and playing down the risk to public health.

Luxembourg said that eggs sold in branches of the discount supermarket Aldi had been withdrawn, with one batch containing so much fipronil it was unsafe to be eaten by young children. Aldi earlier this month pulled all Dutch eggs from its stores in Germany.

Tests also found fipronil in eggs sold in Luxembourg supermarket chain Cactus, which had originally come from the Netherlands, while two Luxembourg suppliers of prepared meals, Caterman and Carnesa, said they had received cartons of liquid eggs from a contaminated source in Belgium.

Some of those eggs had been used in minced beef and luncheon meat but the items had been removed, they said.

The eggs at the centre of the scandal have mainly come from the Netherlands, followed by Belgium and Germany. Dozens of farms have been shut.

Sweden, Switzerland, Britain, France and Luxembourg have also now announced that they have found contaminated eggs.

The problem is believed to stem from a substance used by Dutch company Chickfriend which farmers in the Netherlands and Belgium say they hired to treat their chickens.

A lawyer for a Belgian company, Poultry-Vision, says the firm sold it to Chickfriend but has not said where it got the substance.

The French government says a Belgian company—which it did not identify—mixed fipronil with another, lawful, substance.

UPDATE

Dutch investigators arrested two suspects Thursday in connection with a probe into the discovery of fipronil insecticide in European eggs, prosecutors said.

“It relates to two managers at the company that allegedly used the substance (fipronil) at poultry farms,” spokeswoman Marieke van der Molen said, with Dutch media naming the suspects’ company as Chickfriend.

The arrests came after coordinated raids with Belgian authorities at eight locations across The Netherlands with the assistance of Europe’s policing and judicial agencies Europol and Eurojust.

“The Dutch investigation focused on the Dutch company that allegedly used fipronil, a Belgian supplier as well as a Dutch company that colluded with the Belgian supplier,” prosecutors said.

“They are suspected of putting public health in danger by supplying and using fipronil in pens containing egg-laying chickens,” a statement said.

The two men were arrested in central and southern Netherlands in the towns of Barneveld and Zaltbommel.

Police also searched homes in nearby Bergen op Zoom and Uden as well as a storage shed in Ede and two undisclosed locations.

Investigators confiscated paperwork, as well as cars, banking details, and fixed assets.

Dutch prosecutors said they already started a criminal probe in mid-July into how fipronil, which can harm human health, got into the food chain.

The scandal has spread across eight European countries so far with authorities ordering the destruction of millions of eggs and supermarkets in several nations removing eggs from their shelves.

Fipronil is commonly used in veterinary products to get rid of fleas, lice and ticks but it is banned by the EU from being used to treat animals destined for human consumption, such as chickens.

In large quantities, the insecticide is considered by the World Health Organisation (WHO) to be “moderately hazardous” and can have dangerous effects on people’s kidneys, liver and thyroid glands.

The problem is believed to stem from a substance used by Chickfriend, that farmers in the Netherlands say they hired to treat their chickens.

A lawyer for a Belgian company, Poultry-Vision, says the firm sold it to Chickfriend but has not said where it got the substance.